In the Fredrikson et al U.S. Pat. application Ser. No. 499,759, filed Aug. 22, 1974, having the same assignee as the instant application a metallurgical furnace is disclosed, the furnace basically comprising a vessel which tilts between substantially vertical and horizontal positions and having a refractory lining for containing a melt, such as a steel melt, to be finished as by being desulfurized, receiving alloying additions and the like or otherwise being treated. The vessel is vertically elongated and has the appearance of a Bessemer convertor, but the vessel is provided in its lower portion with a channel-type electric inductor so that the melt can receive heat during its treatment, thus permitting the addition of materials which not only do not exothermically result in heating the melt, but also which may result in having a cooling effect on the melt.
The inductor angles diagonally downwardly from one side of the vessel in a direction resulting in the inductor's channel always retaining sump metal when the vessel is tilted at its horizontal position, the opposite side which is uppermost when the vessel is horizontal, being provided with a nozzle for the injection of the fluid. The fluid can be an inert gas carrying particles of materials to be injected into the melt, the nozzle being positioned so that when the vessel is vertical, the nozzle is below the melt level.
In the operation of this furnace in its vertical position, when the fluid is being injected into the melt, the nozzle is subjected to rapid wear. With this in mind, the Folgero et al U.S. Pat. application Ser. No. 560,204, filed Mar. 20, 1975, having the same assignee as the instant application discloses a nozzle for the vessel of the Fredrikson et al application, which is made so that it is easily removable. In addition, this nozzle, having the necessary fluid-injection passage, has a mass of metal, such as copper, surrounding the passage at a position spaced outwardly from the melt, this mass being provided with cooling means and functioning to cool and freeze any inadvertent outward flow of the melt, such as might result from failure of fluid blast injection equipment, thus plugging the passage and preventing a melt break-out backwardly or outwardly through the nozzle's passage.
In addition to the nozzle wear or erosion, the furnace of the Fredrikson et al patent application presents an additional operational problem in that the portion of the necessary lining of the furnace vessel, immediately above the nozzle, is subjected to substantially greater wear and erosion than is the balance of the lining. Unless this problem is solved, it is necessary to put the furnace out of operation to repair that localized portion of the lining, even though the balance of the lining is potentially capable of a much longer service life.